Laminated glass and interlayer film for laminated glasses

ABSTRACT

A laminated glass and an interlayer film for laminated glasses are provided, which have the high performance for mitigating the impact given externally and, particularly in the case of using it as glass for vehicles, and which have the high performance for mitigating the impact when a person&#39;s head comes into collision with the glass due to the occurrence of a personal accident. Also provided is a laminated glass, wherein at least an interlayer film for laminated glasses and a glass sheet are laminated and unified, Head Injury Criteria (HIC) values, measured according to regulations of European Enhanced Vehicle-safety Committee; EEVC/WG 17, being 1,000 or lower.

This application is a continuation of pending U.S. application Ser. No.10/534,733 filed May 12, 2005 which is a National Stage Entry ofPCT/JP2004/011910 filed Aug. 19, 2004 which claims benefit of priorityunder 35 U.S.C. §119 based on Japanese Patent Application Nos.2003-299375 filed Aug. 22, 2003, 2003-369427, filed Oct. 29, 2003,2003-432892, filed Dec. 26, 2003 and 2004-145471, filed May 14, 2004.The entire disclosures of the prior applications are incorporated hereinby reference.

TECHNICAL FIELD

The present invention relates to a laminated glass and an interlayerfilm for laminated glasses, which have the high performance formitigating the impact given externally and, particularly in the case ofusing it as glass for vehicles, have the high performance for mitigatingthe impact when head comes into collision with the glass due to theoccurrence of a personal accident.

BACKGROUND ART

In recent years, there have been studied and developed systems forevaluating automobile's performance to protect pedestrians when thevehicle comes into collision with a pedestrian in advanced countries.Head portion is largest in number among body parts on which pedestriansare vitally injured in collision with an automobile. Therefore, also ona method of a head impact test for evaluating the protections of headfrom impact, international standards (ISO/SC 10/WG 2) and EU standards(EEVC/WG 10, ECE-Regulation No. 43 Annex 3) are defined.

For example, European Enhanced Vehicle-safety Committee; EEVC/WG 17 hasproposed a test for the protections of head as a part of a test for theprotections of pedestrian and has proposed a condition that a HeadInjury Criteria (HIC) value, which is determined by a method accordingto this test for the protections of head, does not exceed 1,000 as aperformance standard on automobile's safety. Further, an HIC value of1,000 is a threshold of being seriously injured, and it is said thatwhen the HIC value is higher than 1,000, a probability of survival of anormal human being becomes lower.

Front noses of recent automobiles have tendencies to be shortened and inthe recent accidents, a location of vehicles with which the head of anadult pedestrian comes into collision is often a windshield other than ahood.

But, since the test for the protections of head of EEVC/WG 17 limits thescope of test to on the hood of the passenger cars by its definition, inthe ongoing International Harmonized Research Activities (IHRA), it isconsidered to include the windshield in the scope of the test for theprotections of adult head.

Currently, as the glass for vehicles such as automobiles, aircrafts,buildings and the like, laminated glasses are widely employed becauseless fragments of broken glass shatter even though the laminated glassis impacted externally and broken and therefore the laminated glass issafe. As such a laminated glass, there is given a laminated glassobtained by interposing an interlayer film for laminated glasses, whichcomprises polyvinyl acetal resin such as polyvinyl butyral resinplasticized with a plasticizer, between at least a pair of glass sheetsand unifying them and the like.

However, many of conventional laminated glasses have the HIC value ofhigher than 1,000. Especially in windshields of automobiles, the HICvalue is particularly high in the vicinity of a periphery of thewindshield secured to the window's frame and some laminated glasses havean HIC value of higher than 2,000. Such the vicinity of the periphery ofthe windshield is a location with which the head of an adult pedestriancomes into collision at a high probability in the occurrence of anaccident, and a laminated glass having a lower HIC value has beenrequired in order to avoid damages to head in the collision ofpedestrian with vehicles.

DISCLOSURE OF THE INVENTION Problems which the Invention is to Solve

In view of the above-mentioned state of the art, it is an object of thepresent invention to provide a laminated glass and an interlayer filmfor laminated glasses, which have the high performance for mitigatingthe impact given externally and, particularly in the case of using it asglass for vehicles, have the high performance for mitigating the impactwhen head comes into collision with the glass due to the occurrence of apersonal accident.

Means for Solving the Object

The present invention is directed to a laminated glass, wherein at leastan interlayer film for laminated glasses and a glass sheet are laminatedand unified, Head Injury Criteria (HIC) values, measured according toregulations of European Enhanced Vehicle-safety Committee; EEVC/WG 17(hereinafter, also referred to as an HIC value (EEVC)), being 1,000 orlower.

The present invention is directed to a laminated glass, wherein at leastan interlayer film for laminated glasses and a glass sheet are laminatedand unified, Head Injury Criteria (HIC) values, measured according toregulations of Economic Commission for Europe; ECE-Regulation No. 43Annex 3 except for dropping an impactor head from a height of 4 m abovethe surface of the laminated glass (hereinafter, also referred to as HICvalue (ECE)), being 300 or lower.

Incidentally, when the Head Injury Criteria (HIC) value is described asonly an HIC value in this description, it represents any of an HIC value(EEVC) and an HIC value (ECE).

Hereinafter, the present invention will be described in detail.

The laminated glass of the present invention has an HIC value (EEVC),measured according to the regulations of EEVC/WG 17, of 1,000 or lower.If the HIC value is higher than 1,000, in the case of using thelaminated glass of the present invention as glass for vehicles, it isimpossible to avoid damages to head in the collision of pedestrian withvehicles and this causes a probability of survival to decrease. The HICvalue is preferably 600 or lower and more preferably 300 or lower.

In the laminated glass of the present invention, the HIC value (EEVC) ismeasured by colliding an impactor head at a speed of 11.1 m/s to acentral portion of a laminated glass when the laminated glass having asize of 600 mm×600 mm is secured to a frame having an opening of 500mm×500 mm.

FIG. 1 is an exploded perspective view showing schematically a sample ofan HIC value measuring apparatus used in measuring HIC values (EEVC) ofthe laminated glass of the present invention.

As shown in FIG. 1, the HIC value measuring apparatus 10 is mainlycomposed of a supporting portion 11 in the form of box, provided with aflange portion 12 on which a peripheral portion of a laminated glass isrested at the top end, a securing portion 13 having the approximatelysame shape as the flange portion 12 and an impactor head 14 having aconfiguration imitating a human head.

The flange portion 12 of the supporting portion 11 and the securingportion 13 are provided with a plurality of through holes (not shown) atthe corresponding positions, respectively, and after the laminated glassof which the HIC value is measure is rested on the flange portion 12 andthe securing portion 13 is placed on the laminated glass at specifiedpositions, fastening members such as a screw are screwed into thethrough holes, and thereby the laminated glass can be held and securedat its peripheral portion.

That is, in the HIC value measuring apparatus shown in FIG. 1, an innerradius of the flange portion 12 and the securing portion 13 has a sizeof 500 mm×500 mm.

In the impactor head 14, a hemispherical resin head skin is attached toa metal core and an acceleration sensor to measure an acceleration in atriaxial direction is provided at the center within the above core.

Such an impactor head 14 is located above the laminated glass held andsecured as described above, and the above-mentioned acceleration sensorsenses an impact at the moment when colliding the impactor head to thesurface of the laminated glass under the conditions described above tomeasure an HIC value of the laminated glass.

The HIC value (EECV) can be determined by the following equation (1)according to the regulations of EEVC/WG 17 after arranging the apparatusat specified position as described above.

(Equation 1)

$\begin{matrix}{{{HIC} = {\lbrack {\frac{1}{( {t_{2} - t_{1}} )}{\int_{1}^{2}{a_{r}{\mathbb{d}t}}}} \rbrack^{2.5}( {t_{2} - t_{1}} )_{\max}}}{{{but}\mspace{14mu} a_{r}} = \sqrt{a_{I}^{2} + a_{F}^{2} + a_{S}^{2}}}} & (1)\end{matrix}$

In the equation (1), a_(r) represents a synthesized acceleration (G) ofthe impactor head, a_(I) represents an acceleration (G) in the directionof travel of the impactor head, a_(F) represents an forward and backwardacceleration (G) of the impactor head, as represents a lateralacceleration (G) of the impactor head, and t₂−t₁ represents a time span(maximum 0.015 seconds) at which the HIC value is maximized.

In the laminated glass of the present invention, the HIC value (ECE),measured by dropping an impactor head from a height of 4 m above thesurface of the laminated glass according to regulations ofECE-Regulation No. 43 Annex 3, is 300 or lower. By reducing the HICvalue (ECE) below 300, it becomes possible to reduce HIC value also in aperiphery of the windshield secured to the window's frame and it ispossible to avoid the damages to head in the collision of pedestrianwith vehicles and a probability of survival becomes higher. The HICvalue is preferably 250 or lower.

In the laminated glass of the present invention, the HIC value (ECE) ismeasured by colliding an impactor head at dropping height of 4 m to acentral portion of a laminated glass when the laminated glass having asize of 1,100 mm×500 mm is secured to a frame having an opening of 1,070mm×470 mm. In this time, a collision speed of the impactor head is 8.9m/s.

FIG. 2 is a view showing schematically a sample of an HIC valuemeasuring apparatus used in measuring HIC values (ECE) of the laminatedglass of the present invention.

As shown in FIG. 2, the HIC value measuring apparatus is composed of alaminated glass stage 21 having a structure similar to that in HICvalues (EECV) described above, an impactor head 22 having aconfiguration imitating a human head and a guide system 23 to drop theimpactor head vertically.

The constitution of the impactor head is described in detail inregulations of ECE-Regulation No. 43 Annex 3, and for example, metalplates are attached to a top and a bottom of a wood constituent body,respectively, and a hemisphere made from polyamide resin is attached asshown in Figure to assemble a pear-like head. An acceleration sensor tomeasure an acceleration in a triaxial direction is equipped on a baseplate and a rubber head skin is attached to the hemisphere made frompolyamide resin which is located at the bottom. A weight of the impactorhead is 10 kg.

The guide system 23 includes a mechanism to carry/detach an impactorhead 22 and it is dropped with the mechanism carrying the impactor head22 from a specified height (4 m in the present invention). A state of afall in doing so is observed with an optical sensor 24 and the impactorhead 22 is detached from the guide system 23 at the moment when theimpactor head 22 passes by a position of the optical sensor. Theimpactor head detached from the guide system 23 falls freely and comesinto collision with a central portion of a laminated glass secured tothe support 21 of a laminated glass. An impact in this time is sensed bythe above-mentioned acceleration sensor to measure an HIC value (ECE) ofthe laminated glass.

The HIC value (ECE) can be determined by the above-mentioned equation(1) as with the HIC value (EECV).

Both the HIC value (EECV) and the HIC value (ECE) are standards definedby European official agencies. The HIC value (EECV) and the HIC value(ECE) are different from each other in a measuring method and criteria,and it is difficult to make a direct comparison between them. However,generally, it can be said that the HIC value (ECE) is 300 or lower ismore tough than that the HIC value (EEVC) is 1,000 or lower as astandard. Accordingly, there may be cases where even though a laminatedglass can achieve the HIC value (EEVC) of 1,000 or lower, it cannotachieve the HIC value (ECE) of 300 or lower. Though the laminated glassof the present invention includes both a substance of the HIC value(EEVC) of 1,000 or lower and a substance of the HIC value (ECE) of 300or lower, it is preferred that the HIC value (ECE) is 300 or lower.

A laminated glass which can achieve such a low HIC value is notparticularly limited and includes (1) a laminated glass to absorb animpact with a interlayer film for laminated glasses, (2) a laminatedglass to absorb an impact by reducing a thickness of a glass portion toreadily deform or shatter in collision, and (3) a laminated glass inwhich by replacing glass on one side (inner side in using the laminatedglass as glass for vehicles) of a laminated glass with a resin plate,impact-absorbency of the overall laminated glass is enhanced.

Hereinafter, respective cases will be described in detail.

First, (1) the case of absorbing an impact with the interlayer film forlaminated glasses will be described.

An interlayer film for laminated glasses used in this case is notparticularly limited but an interlayer film for laminated glasses, inwhich a plasticizer for interlayer films is contained in an amount 30parts by weight or more per 100 parts by weight of polyvinyl acetalresin, is suitably used. It is possible to reduce the HIC value of thelaminated glass by using the interlayer film for laminated glasses, inwhich such a large amount of plasticizer for interlayer films isblended. An amount of the plasticizer for interlayer films to be blendedis more preferably 40 parts by weight or more, furthermore preferably 45parts by weight or more, and particularly preferably 60 parts by weightor more. When the above-mentioned interlayer film for laminated glasseshas a multilayer structure of two-layers or more, the HIC value of thelaminated glass can be reduced by having a resin layer of theabove-mentioned constitution in at least one layer.

The above-mentioned polyvinyl acetal resin is not particularly limitedbut polyvinyl acetal resin having an acetalization degree of 60 to 85mol % is suitable. The acetalization degree is more preferably 65 to 80mol %.

Incidentally, in this description, the “acetalization degree” refers toan acetalization degree derived by a method of counting two acetalizedhydroxyl groups since an acetal group of polyvinyl acetal resin isformed by acetalizing two hydroxyl groups of poly alcohol resin to be araw material.

As the above-mentioned polyvinyl acetal resin, polyvinyl acetal resin,in which a half band width of a peak of a hydroxyl group, obtained inmeasuring infrared absorption spectra, is 250 cm⁻¹ or less, is suitable.The half band width is more preferably 200 cm⁻¹ or less.

Here, as a method of measuring the infrared absorption spectrum of theabove-mentioned interlayer film for laminated glasses, there is given amethod of using, for example, “FT-IR” manufactured by HORIBA, Ltd. tomeasure the infrared absorption spectrum and the half band width can bedetermined from a peak, corresponding to a hydroxyl group, of theobtained peaks.

As a method of producing the above-mentioned polyvinyl acetal resin,there are given, for example, a method of dissolving polyvinyl alcoholin hot water, adding an acid catalyst and aldehyde to the obtainedaqueous solution of polyvinyl alcohol while keeping the aqueous solutionat 0 to 90° C., preferably 10 to 20° C., allowing an acetalizationreaction to proceed while stirring, raising a reaction temperature to70° C. to age the reactant and complete the reaction, and thenconducting neutralization, water washing and drying to obtain powder ofpolyvinyl acetal resin.

The above-mentioned aldehyde is not limited and includes, for example,aliphatic aldehydes, aromatic aldehydes and alicyclic aldehydes such aspropionaldehyde, n-butylaldehyde, iso-butylaldehyde, valeraldehyde,n-hexyl aldehyde, 2-ethylbutyl aldehyde, n-heptyl aldehyde,n-octylaldehyde, n-nonyl aldehyde, n-decyl aldehyde, benzaldehyde,cinnamaldehyde. The above-mentioned aldehyde is preferablyn-butylaldehyde, n-hexyl aldehyde, 2-ethylbutyl aldehyde and n-octylaldehyde, having 4 to 8 carbon atoms. N-butylaldehyde having 4 carbonatoms is more preferred since weathering resistance is excellent throughuse of polyvinyl acetal resin to be obtained and in addition theproduction of resin becomes easy. These aldehydes may be used alone orin combination of two or more species.

The above-mentioned polyvinyl acetal resin may be crosslinked one. Byusing crosslinked polyvinyl acetal resin, the bleed-out of a plasticizerfor interlayer films can be inhibited.

As a method of crosslinking the above-mentioned polyvinyl acetal resin,there are given, for example, a method of partially crosslinking betweenmolecules with a diacetal bond using dialdehyde such as glutaraldehydein acetalizing polyvinyl alcohol by aldehyde such as butyl aldehyde; amethod in which in an acetalization reaction of polyvinyl alcohol, afterreaching at least 90% of intended acetalization degree, an acid catalystis added to this reactant and the mixture is reacted at 60 to 95° C.,and thereby, crosslinking is formed between molecules of polyvinylacetal with a monobutyral bond; a method of adding a crosslinking agentwhich is reactive with a hydroxyl group remaining in an obtainedpolyvinyl acetal resin to cross-link the hydroxyl group; and a method ofcross-linking a hydroxyl group remaining in polyvinyl acetal resin bydiisocyanate and polyhydric epoxy.

As the above-mentioned crosslinking agent which reacts with a hydroxylgroup, there are given, for example, dialdehydes such as glyoxal,dialdehydes containing a sulfur atom in a molecular chain,glyoxal-ethylene glycol reactant, polyvinyl alcohol modified withaldehyde at both ends, dialdehyde starch, polyacrolein; methylols suchas N-methylolurea, N-methylolmelamine, trimethylolmelamine,hexamethylolmelamine; epoxies such as α-hydroxyethylsulfonic acid,epichlorohydrin, polyethyleneglycol diglycidyl ether, diglycidyletherified bisphenol A type epoxy resin, polypropylene glycol diglycidylether, neopentyl glycol diglycidyl ether, diglycidyl etherifiedglycerin, polyethylene glycol having three or more glycidyl ether groupsin a molecular chain, polyglycidyl ether modification product oftrimethylolpropane, polyglycidyl ether modification product of sorbitol,polyglycidyl ether modification product of sorbitan, polyglycidyl ethermodification product of polyglycerol; polyhydric carboxylic acids suchas dicarboxylic acid, Michael adduct of triethylene glycol and methylacrylate, polyacrylic acid, mixture of methyl vinyl ether-maleic acidcopolymer and isobutylene-maleic anhydride copolymer; aromaticdiisocyanates such as trilene diisocyanate, phenylene diisocyanate,4,4′-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate;aliphatic diisocyanates such as hexamethylene diisocyanate, xylylenediisocyanate, ridine diisocyanate, 4,4′-dicyclohexylmethanediisocyanate, isophorone diisocyanate; and polyisocyanate blocked withpolyphenol, acetyl acetone, diethyl malonate, lactam, oxime, amide ortertiary alcohol etc.

When the above-mentioned interlayer film for laminated glasses comprisescrosslinked polyvinyl acetal resin, the above-mentioned interlayer filmfor laminated glasses preferably has a thickness of 800 μm or more. Whenthe thickness is less than 800 μm, low HIC value may not be adequatelyattained.

The above-mentioned plasticizer for interlayer films is not particularlylimited as long as it is one generally used in polyvinyl acetal resinand publicly known plasticizers which are generally used as aplasticizer for interlayer films can be used. As such a plasticizer forinterlayer films, there are given, for example, organic ester typeplasticizers such as monobasic acid ester, polybasic acid ester; andphosphoric acid type plasticizers such as organic phosphoric acid type,organic phosphorous acid type. These plasticizers may be used alone ormay be used in combination of two or more species and are selectivelyused depending on the species of the polyvinyl acetal resin inconsideration of the compatibility with resins.

The above-mentioned monobasic acid ester type plasticizer is notparticularly limited and includes, for example, glycol type estersobtained by a reaction between glycol such as triethylene glycol,tetraethylene glycol or tripropylene glycol and organic acid such asbutyric acid, isobutyric acid, capric acid, 2-ethylbutyric acid,heptylic acid, n-oxtylic acid, 2-ethylhexyl acid, pelargonic acid(n-nonylic acid) or decylic acid. Among others, there are suitably usedmonobasic organic acid esters of triethylene glycol such as triethyleneglycol-dicapric acid ester, triethylene glycol-di-2-ethylbutyric acidester, triethylene glycol-di-n-octylic acid ester, triethyleneglycol-di-2-ethylhexyl acid ester.

The above-mentioned polybasic acid ester type plasticizer is notparticularly limited and includes, for example, ester of polybasicorganic acid such as adipic acid, sebacic acid or azelaic acid andstraight-chain or branched alcohol having 4 to 8 carbon atoms. Amongothers, dibutyl sebacare, dioctyl azelate, dibutyl carbitol adipate aresuitably used.

The above-mentioned organic ester type plasticizer is not particularlylimited but for example, triethylene glycol di-2-ethylbutyrate,triethylene glycol di-2-ethylhexoate, triethylene glycol dicaprate,triethylene glycol di-n-2-octoate, triethylene glycol di-n-heptoate,tetraethylene glycol di-n-heptoate, dibutyl sebacare, dioctyl azelateand dibutyl carbitol adipate are suitably used.

As the above-mentioned plasticizer, in addition to these, there also canbe used, for example, ethylene glycol di-2-ethylbutyrate, 1,3-propyleneglycol di-2-ethylbutyrate, 1,4-propylene glycol di-2-ethylbutyrate,1,4-butylene glycol di-2-ethylbutyrate, 1,2-butylene glycoldi-2-ethylenebutyrate, diethylene glycol di-2-ethylbutyrate, diethyleneglycol di-2-ethylhexoate, dipropylene glycol di-2-ethylbutyrate,triethylene glycol di-2-ethylpentoate, tetraethylene-glycoldi-2-ethylbutyrate and diethylene glycol dicapriate.

The above-mentioned phosphoric acid type plasticizer is not particularlylimited but for example, tributoxyethyl phosphate, isodecylphenylphosphate and triisopropyl phosphite are suitable.

Among these plasticizer for interlayer films, there are particularlysuitably used diester type compounds comprising dicarboxylic acid andmonohydric alcohol or comprising monocarboxylic acid and dihydricalcohol.

And, as the above-mentioned interlayer film for laminated glasses, ainterlayer in which rubber particles are dispersed is suitable. Whensuch rubber particles are dispersed, it is possible to absorb an impactas force is applied to the interlayer film for laminated glasses.

The above-mentioned rubber particle is not particularly limited but forexample, a crosslinked resin of polyvinyl acetal is suitable from thefact that it has a refractive index close to that of surrounding resinand it hardly causes deterioration of the visible transmittance of aninterlayer film for laminated glasses to be obtained from thecrosslinked resin of polyvinyl acetal. A particle size of theabove-mentioned rubber particle is not particularly limited but it ispreferably 1.0 μm or smaller, and an amount of the above-mentionedrubber particles to be blended is not particularly limited but apreferable lower limit is 0.01 parts by weight and a preferable upperlimit is 10 parts by weight with respect to 100 parts by weight of resinsuch as polyvinyl acetal resin.

As the above-mentioned interlayer film for laminated glasses, there aresuitably used an interlayer film in which a storage elasticity modulusG′ in a linear dynamic viscoelasticity test, which is measured withfrequencies varied by a shear method at 20° C. in a range of frequenciesof 5.0×10¹ to 1.0×10² Hz, is 3×10⁷ Pa or lower; an interlayer film inwhich tan δ of at least one point is 0.6 or more at 20° C. in a range offrequencies of 5.0×10¹ to 1.0×10² Hz; and an interlayer film in whichmaximum stress σ, which is derived from a stress-deformation curve at20° C. and a tensile speed of 500%/min, is 20 MPa or smaller andfracture point deformation ε derived similarly of 200% or more.

The above-mentioned storage elasticity modulus G′ is a valuerepresenting softness of the interlayer film for laminated glasses. Byusing an adequately soft interlayer film for laminated glasses, alaminated glass to be obtained becomes low in the HIC value. When thestorage elasticity modulus G′ exceeds 3.0×10⁷ Pa, the HIC value (EEVC)of the laminated glass to be obtained may exceed 1,000 or the HIC value(ECE) may exceed 300. The storage elasticity modulus G′ is morepreferably 1.0×10⁷ Pa or lower and furthermore preferably 5.0×10⁶ Pa orlower.

And, in the above-mentioned interlayer film for laminated glasses, it ispreferred that a storage elasticity modulus E′ in a viscoelasticitytest, which is measured with frequencies varied by a tensile method at20° C. in a range of frequencies of 5.0×10¹ to 1.0×10² Hz, is 1.0×10⁹ Paor lower. The above-mentioned storage elasticity modulus E′ is also avalue representing softness of the interlayer film for laminatedglasses. By using an adequately soft interlayer film for laminatedglasses, a laminated glass to be obtained becomes low in the HIC value.When the storage elasticity modulus E′ exceeds 1.0×10⁹ Pa, the HIC value(EEVC) of the laminated glass to be obtained may exceed 1,000 or the HICvalue (ECE) may exceed 300. The storage elasticity modulus E′ is morepreferably 0.5×10⁹ Pa or lower and furthermore preferably 5.0×10⁶ Pa orlower.

The above-mentioned tan δ is a ratio between a storage elasticitymodulus G′ measured with frequencies varied by a shear method and a lossmodulus G″ (G″/G′) and a value showing dynamic viscoelasticity of theinterlayer film for laminated glasses, and by extension the absorbencyof impact energy. By using an interlayer film for laminated glasseshaving an adequately high absorbency of impact energy, a laminated glassto be obtained becomes low in the HIC value. When the tan δ is less than0.6, the HIC value (EEVC) of the laminated glass to be obtained mayexceed 1,000 or the HIC value (ECE) may exceed 300. The tan δ is morepreferably 0.7 or more.

Further, a measuring frequency of the above-mentioned storage elasticitymodulus G′, storage elasticity modulus E′ and tan δ is within a range of5.0×10¹ to 1.0×10² Hz, and this represents deformation of 10 to 20 msecand measuring result of a region including a maximum time span, 15 msec,of the HIC value measurement. In the measurement of the HIC value,deformation in a short time span of shorter than 10 msec may becomepredominant to measurement, but it is possible to analogize easily frommeasurements in 5.0×10¹ to 1.0×10² Hz up to the order of 1.0×10² to3.0×10² Hz (represent 3.3 to 10 msec). Therefore, since measurements ofthe storage elasticity modulus G′, storage elasticity modulus E′ and tanδ in a range of a frequency of 5.0×10¹ to 1.0×10² Hz satisfy theabove-mentioned conditions, it is thought that the HIC value can beadequately reduced.

When the above-mentioned maximum stress σ and fracture point deformationε remain in the range described above, the interlayer film for laminatedglasses can absorb impact energy by stretching within 15 msec incollision and a laminated glass using such an interlayer film forlaminated glasses becomes low in the HIC value. The above-mentionedmaximum stress σ is more preferably 18 MPa or smaller and furthermorepreferably 16 MPa or smaller. The above-mentioned fracture pointdeformation ε is more preferably 300% or more and furthermore preferably400% or more.

In addition, a stress-deformation curve of the above-mentionedinterlayer film for laminated glasses can be drawn, for example, bystretching a specimen of the interlayer film for laminated glasses at20° C. and a tensile speed of 500%/min with a dumbbell No. 1 using atension tester according to JIS K 6771 to measure resistance (kg/cm²).And, the above-mentioned maximum stress σ is a maximum value of theabove-mentioned resistance and the above-mentioned fracture pointdeformation ε is a value of the deformation shown at the time offracture of the above-mentioned specimen.

When the maximum stress σ and the fracture point deformation ε, thusderived, satisfy the above-mentioned conditions, breaking energy U ofthe above-mentioned interlayer film for laminated glasses is preferably1.0 J/mm² or larger. Here, the breaking energy U can be derived from thestress σ and the deformation ε of the interlayer film for laminatedglasses in a tensile test under the above-mentioned conditions using thefollowing equation (2).U=∫σdε  (2)

The above-mentioned interlayer film for laminated glasses may becomposed of only a layer comprising resin composition in which aplasticizer for interlayer films is contained in an amount 30 parts byweight or more per 100 parts by weight of the polyvinyl acetal resindescribed above but preferably it has a multilayer structure includingsuch a layer.

When the interlayer film for laminated glasses is composed of only alayer comprising resin composition in which a plasticizer for interlayerfilms is contained in an amount 30 parts by weight or more per 100 partsby weight of the polyvinyl acetal resin, there may be cases where it islow in basic various performance required as glass for vehicles, such asresistance to penetrating through glass, although it can reduce the HICvalue. For example, in the laminated glass of the present invention, animpactor dropping height measured by an impactor dropping height test ispreferably 4 m or higher. When this height is less than 4 m, theresistance to penetrating through glass of the overall laminated glassbecomes insufficient and the laminated glass may not be employed asglass for vehicles. This height is more preferably 5 m or higher andfurthermore preferably 7 m or higher.

By employing the multilayer structure, the HIC value is reduced througha layer comprising resin composition in which a plasticizer forinterlayer films is contained in an amount 30 parts by weight or moreper 100 parts by weight of the polyvinyl acetal resin and simultaneouslythe performance such as resistance to penetrating through glass is addedthrough another layers, and therefore one of different functions iscompatible with another.

The interlayer film for laminated glasses having the multilayerstructure is not particularly limited but a preferable constitution willbe described in detail by the following descriptions.

When the interlayer film for laminated glasses has a two-layersstructure, it is preferred that a storage elasticity modulus G′ at 20°C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one layer is at or belowa half of a storage elasticity modulus G′ at 20° C. and a frequency of5.0×10¹ to 1.0×10² Hz in the other layer. In this time, it is morepreferred that a storage elasticity modulus G′ at 20° C. and a frequencyof 5.0×10¹ to 1.0×10² Hz in one layer is 2×10⁶ Pa or lower and a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin the other layer is 1×10⁷ Pa or higher, and it is furthermorepreferred that the above-mentioned layer, in which the storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzis 2×10⁶ Pa or lower, has tan δ of 0.7 or more at 20° C. and a frequencyof 5.0×10¹ to 1.0×10² Hz.

And, in such an interlayer film for laminated glasses, it is preferredthat a thickness of the above-mentioned layer, in which the storageelasticity modulus G′ is 2×10⁶ Pa or lower, is 10% or higher of a totalthickness of the interlayer film for laminated glasses. When thisthickness of the above-mentioned layer is lower than 10% of the totalthickness of the interlayer film for laminated glasses, it may beimpossible to realize a low HIC value. It is more preferably 14% orhigher and furthermore preferably 20% or higher.

When the interlayer film for laminated glasses having such a two-layersstructure is employed, the low HIC value is compatible with theresistance to penetrating through glass.

When the interlayer film for laminated glasses has a three-layersstructure, it is preferred that a storage elasticity modulus G′ at 20°C. and a frequency of 5.0×10¹ to 1.0×10² Hz in an intermediate layer isat or below a half of a storage elasticity modulus G′ at 20° C. and afrequency of 5.0×10¹ to 1.0×10² Hz in one or any of two layers composingthe outermost layer. In this time, it is more preferred that a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin the intermediate layer is 2×10⁶ Pa or lower and a storage elasticitymodulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one orany of two layers composing the outermost layer is 1×10⁷ Pa or higher,and it is furthermore preferred that the intermediate layer has tan δ of0.7 or more at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz.

In addition, it is preferred that a storage elasticity modulus G′ of theabove-mentioned intermediate layer is at or below a half of a storageelasticity modulus G′ of one of two layers composing the outermostlayer, and it is more preferred that it is at or below a half of astorage elasticity modulus G′ of any of two layers composing theoutermost layer.

And, in such an interlayer film for laminated glasses, it is preferredthat a thickness of the above-mentioned intermediate layer is 10% orhigher of a total thickness of the interlayer film for laminatedglasses. When this thickness is lower than 10% of the total thickness ofthe interlayer film for laminated glasses, it may be impossible torealize a low HIC value. It is more preferably 14% or higher andfurthermore preferably 20% or higher.

When the interlayer film for laminated glasses having such athree-layers structure is employed, the low HIC value is compatible withthe resistance to penetrating through glass, and further it is possibleto develop the performance such as resistance to blocking between theinterlayer films for laminated glasses.

When the interlayer film for laminated glasses has a multilayerstructure of four-layers or more, it is preferred that a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin at least one layer of an intermediate layer is at or below a half ofa storage elasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to1.0×10² Hz in one or any of two layers composing the outermost layer. Inthis time, it is more preferred that a storage elasticity modulus G′ at20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in the above-mentionedintermediate layer is 2×10⁶ Pa or lower and a storage elasticity modulusG′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one or any oftwo layers composing the outermost layer is 1×10⁷ Pa or higher, and itis furthermore preferred that tan δ of the intermediate layer, in whichthe storage elasticity modulus G′ is 2×10⁶ Pa or lower, at 20° C. and afrequency of 5.0×10¹ to 1.0×10² Hz is 0.7 or more.

In addition, it is preferred that a storage elasticity modulus G′ of theabove-mentioned at least one layer of the intermediate layer is at orbelow a half of a storage elasticity modulus G′ of one of two layerscomposing the outermost layer, and it is more preferred that it is at orbelow a half of a storage elasticity modulus G′ of any of two layerscomposing the outermost layer.

And, in such an interlayer film for laminated glasses, it is preferredthat a thickness of the above-mentioned intermediate layer, in which thestorage elasticity modulus G′ is 2×10⁶ Pa or lower, is 10% or higher ofa total thickness of the interlayer film for laminated glasses. Whenthis thickness is lower than 10% of the total thickness of theinterlayer film for laminated glasses, it may be impossible to realize alow HIC value. It is more preferably 14% or higher and furthermorepreferably 20% or higher.

In the case where the above-mentioned interlayer film for laminatedglasses has a multilayer structure of three-layers and four-layers ormore, it is preferred that the intermediate layer, having the storageelasticity modulus G′ of 2×10⁶ Pa or lower, is biased to the side ofeither surface layer with respect to the thickness direction of theinterlayer film for laminated glasses. When the laminated glass of sucha interlayer film for laminated glasses is attached to vehicles and thelike in such a way that the side of the interlayer, to which theintermediate layer having the storage elasticity modulus G′ of 2×10⁶ Paor lower is biased, faces outside the vehicles, the HIC value can bereduced in this direction.

As a method of biasing the intermediate layer having the storageelasticity modulus G′ of 2×10⁶ Pa or lower to the side of either surfacelayer like this, there are given, for example, a method of increasing athickness of one outermost layer 1.2 or more times larger than that ofthe other outermost layer, more preferably 1.5 or more times andfurthermore preferably 2.0 or more times and the like.

When the interlayer films for laminated glasses having such a multilayerstructure of three-layers and four-layers or more are employed, the lowHIC value is compatible with the resistance to penetrating throughglass.

And, when the interlayer film for laminated glasses has a three-layersstructure, it is preferred that a storage elasticity modulus G′ at 20°C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one or any of two layerscomposing the outermost layer is at or below a half of a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin an intermediate layer.

In this time, it is preferred that a storage elasticity modulus G′ at20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one or any of twolayers composing the outermost layer is 2×10⁶ Pa or lower and a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin the intermediate layer is 1×10⁷ Pa or higher, and it is furthermorepreferred that tan δ of one or any of two layers composing the outermostlayer at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz is 0.7 or more.

In addition, it is preferred that a storage elasticity modulus G′ of theabove-mentioned one of two layers composing the outermost layer is at orbelow a half of a storage elasticity modulus G′ of the intermediatelayer, and it is more preferred that a storage elasticity modulus G′ ofany of two layers composing the outermost layer is at or below a half ofthe storage elasticity modulus G′ of the intermediate layer.

And, in such an interlayer film for laminated glasses, it is preferredthat a total thickness of the above-mentioned outermost layer is 10% orhigher of a total thickness of the interlayer film for laminatedglasses. When this thickness is lower than 10% of the total thickness ofthe interlayer film for laminated glasses, it may be impossible torealize a low HIC value. It is more preferably 14% or higher andfurthermore preferably 20% or higher.

When the interlayer film for laminated glasses having such athree-layers structure is employed, the low HIC value is compatible withthe resistance to penetrating through glass.

And, when the interlayer film for laminated glasses has a multilayerstructure of four-layers or more, it is preferred that a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin one or any of two layers composing the outermost layer is at or belowa half of a storage elasticity modulus G′ at 20° C. and a frequency of5.0×10¹ to 1.0×10² Hz in at least one layer of layers composing anintermediate layer. In this time, it is more preferred that a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin one or any of two layers composing the outermost layer is 2×10⁶ Pa orlower and a storage elasticity modulus G′ at 20° C. and a frequency of5.0×10¹ to 1.0×10² Hz in the intermediate layer is 1×⁷ Pa or higher, andit is furthermore preferred that one or any of two layers composing theoutermost layer has tan δ of 0.7 or more of at 20° C. and a frequency of5.0×10¹ to 1.0×10² Hz.

In addition, it is preferred that a storage elasticity modulus G′ of theabove-mentioned one of two layers composing the outermost layer is at orbelow a half of a storage elasticity modulus G′ of at least one layer oflayers composing the intermediate layer, and it is more preferred that astorage elasticity modulus G′ of any of two layers composing theoutermost layer is at or below a half of the storage elasticity modulusG′ of the intermediate layer.

And, in such an interlayer film for laminated glasses, it is preferredthat a total thickness of the outermost layer is 10% or higher of atotal thickness of the interlayer film for laminated glasses. When thisthickness is lower than 10% of the total thickness of the interlayerfilm for laminated glasses, it may be impossible to realize a low HICvalue. It is more preferably 14% or higher and furthermore preferably20% or higher.

In the case where the above-mentioned interlayer film for laminatedglasses has a multilayer structure of three-layers and four-layers ormore, it is preferred that the intermediate layer, having the storageelasticity modulus G′ of 1×10⁷ Pa or higher, is biased to the side ofeither surface layer with respect to the thickness direction of theinterlayer film for laminated glasses. When the laminated glass of sucha interlayer film for laminated glasses is attached to vehicles and thelike in such a way that the side of the interlayer film for laminatedglasses, to which the intermediate layer having the storage elasticitymodulus G′ of 1×10⁷ Pa or higher is biased, faces inside the vehicles,the HIC value can be reduced in this direction.

As a method of biasing the intermediate layer having the storageelasticity modulus G′ of 1×10⁷ Pa or higher to the side of eithersurface layer like this, there are given, for example, a method ofincreasing a thickness of one outermost layer 1.2 or more times largerthan that of the other outermost layer, more preferably 1.5 or moretimes and furthermore preferably 2.0 or more times and the like.

When the interlayer films for laminated glasses having such a multilayerstructure of three-layers and four-layers or more are employed, the lowHIC value is compatible with the resistance to penetrating throughglass.

In the case where the above-mentioned interlayer film for laminatedglasses employs the multilayer structure, the respective resin layerscomposing the above-mentioned interlayer film for laminated glasses ofthe multilayer structure preferably have different adhesion in order torealize the above constitution, and for example in the case where therespective resin layers comprise mainly polyvinyl acetal resin, it isconceivable to use a combination of layers in which the content of aplasticizer in each layer is different from each other by an amount of 5or more parts by weight with respect to 100 parts by weight of thepolyvinyl acetal; the respective resin layers comprise resins havingdifferent compositions such as the layer comprise polyethyleneterephthalate film and polyvinyl acetal resin; amounts of adhesioncontrol agents blended into the respective resin layers are different;and the respective resin layers have different acetalization degrees.

The above-mentioned adhesion control agent is not particularly limitedand by containing metal salt of carboxylate having 2 to 6 carbon atomsin the above-mentioned resin layer, it is possible to adjust adhesion ofan interlayer film for laminated glasses to a glass sheet in a desiredrange and simultaneously to protect the secular degradation of adhesionand protection of whitening is compatible with protection of seculardegradation of adhesion.

As the above-mentioned metal salt of carboxylic acid, there are given,for example, metal salt of pentanoate (5 carbon atoms), metal salt ofhexanoate (2-ethyl butanoate) (6 carbon atoms), metal salt of heptanoate(7 carbon atoms), and metal salt of octanoate (8 carbon atoms). Thesemay be used alone or may be used—in combination of two or more species.And, the above-mentioned carboxylic acid may be a straight-chain type ora side-chain type.

Thickness of the above-mentioned interlayer film for laminated glassesis not particularly limited but a preferable lower limit is 300 μm and apreferable upper limit is 3 mm. A more preferable lower limit is 500 μmand a more preferable upper limit is 2 mm.

In the above-mentioned interlayer film for laminated glasses, embossingmay be applied to the surface of a layer to contact with glass. Byapplying embossing, adhesion of an interlayer film for laminated glassesto a glass sheet can be adjusted in a desired range.

The above-mentioned interlayer film for laminated glasses is preferablyone in which a break of 10 mm or longer in length is generated whenmeasuring the above HIC value (EEVC) or the above HIC value (ECE). Sincegeneration of the break requires more energy than stretching, bybreaking, it is possible to absorb energy of the impactor head andreduce the HIC value. In addition, when the break is not in the form ofa line but a plurality of breaks or a branched break is generated, thetotal length of breaks is preferably 10 mm or longer. More preferablelength of the break is 20 mm or longer, and furthermore preferably 50 mmor longer.

A method of attaining such an interlayer film for laminated glasses isnot particularly limited and includes a method of appropriatelyadjusting breaking tensile strength, breaking extension rate, breakingenergy, etc. of the interlayer film for laminated glasses and inaddition providing slits to facilitate the occurrence of break or weakportions such as a thin portion in part of the interlayer film forlaminated glasses.

By using the interlayer film for laminated glasses described above, alaminated glass realizing the low HIC value can be obtained.

These interlayer films for laminated glasses also constitute the presentinvention.

Next, there will be described the case (2) where an impact is absorbedby reducing a thickness of a glass portion to shatter readily incollision. In this case, a laminated glass, in which a thickness of atleast one glass sheet is 1.8 mm or smaller, is suitably used. Such alaminated glass can absorb an impact through the ease of deformationand/or shattering of glass in collision. In addition, the HIC value ofthe laminated glass has a strong relationship with deformation incollision and the HIC value of the laminated glass decreases as amagnitude of deformation in collision increases. That is, the larger thedeformation of the laminated glass, the smaller the HIC value. And, bythickening the other glass sheet more than 1.8 mm, durability as alaminated glass is compatible with the HIC value.

Incidentally, when a laminated glass of a structure using glass sheetshaving different thickness is used as glass for vehicles, more thickside of the glass may be used as the outside of the vehicle or as theinside of the vehicle, but it is preferably used as the outside of thevehicle in order to enhance the durability as glass.

Next, there will be described the case (3) where by replacing glass onone side (inner side in using the laminated glass as glass for vehicles)of a laminated glass with a resin plate, impact-absorbency of theoverall laminated glass is enhanced. As such a laminated glass, forexample, a substance in which the interlayer film for laminated glassesis sandwiched between a glass sheet and a transparent resin plate ispreferred. When a laminated glass is formed, it is preferred that hazeis 2% or less and an impactor dropping height is 4 m or more. In such alaminated glass, since performance of absorbing an impact is adequatelyhigh compared with a laminated glass of which two sides comprise glass,the HIC value (EEVC) of 1,000 or lower and the HIC value (ECE) of 300 orlower can be attained.

The above-mentioned transparent resin plate is not particularly limitedbut for example, a resin plate comprising polycarbonate, acrylic resin,acrylic copolymerizable resin or polyester resin is preferred because ofbeing excellent in visible transmittance and haze and a resin platehaving an impactor dropping height of 4 m or more is preferred.

And, since above-mentioned transparent resin plate is generally prone tobeing damaged, it is preferably coated with transparent elastomer inorder to use as glass for vehicles.

The above-mentioned transparent elastomer is not particularly limitedand includes, for example, urethane type elastomer, nylon typeelastomer, straight-chain low density polyethylene, etc.

In the laminated glass of the present invention, a method of producing ainterlayer film for laminated glasses is not particularly limited andincludes, for example, a method in which resin component such aspolyvinyl acetal resin described above, a plasticizer and other additiveas required are blended and mixed uniformly and then a film is formed insheet form by conventional methods publicly known such as extrusionprocess, calendar process, press process, casting process and filmblowing process.

A method of producing a interlayer film for laminated glasses, having amultilayer structure, is not particularly limited and includes, forexample, a method in which resin component such as polyvinyl acetalresin described above, a plasticizer and other additive as required areblended and mixed uniformly and then the respective layer are extrudedtogether, and a method of laminating two or more resin films prepared bythe above-mentioned method by press process or laminate process. Thenot-yet-laminated resin film to be used in the method of laminating bypress process or laminate process may be a single layer structure or maybe a multilayer structure.

And, a method of fabricating the laminated glass of the presentinvention is not particularly limited and a publicly known method offabricating laminated glasses can be employed. For example, when thelaminated glass of the present invention has a constitution in which ainterlayer film for laminated glasses is sandwiched between two glasssheets, it can be fabricated by sandwiching the above interlayer filmfor laminated glasses between two glass sheets, putting this in a rubberbag, bonding preliminarily two glass sheets to each other at 70 to 110°C. while evacuating under reduced pressure and then using an autoclaveor pressing to bond two glass sheets to each other in earnest at about120 to 150° C. and a pressure of about 10 to 15 kg/cm².

Further, in the above-mentioned method of fabricating the laminatedglass, a method of interposing an interlayer film for laminated glasses,comprising polyvinyl butyral resin plasticized, between at least a pairof glass sheets, and deaerating by vacuum aspiration and simultaneouslyattaching the glasses to each other by heat and pressure at 60 to 100°C. may be employed. More specifically, the fabrication of the laminatedglass of the present invention is implemented by putting a laminate of aglass sheet/an interlayer film/a glass sheet in a rubber bag andattaching two glass sheets to each other by heat and pressure at atemperature of about 60 to 100° C. and a pressure of about 1 to 10kg/cm² for 10 to 30 minutes, for example, in an autoclave whileaspirating and deaerating under a reduced pressure of about −500 to −700mmHg to perform deaeration and adhesion simultaneously.

In this method of fabrication, adhesion between the interlayer film forlaminated glasses and the glass sheet can be adjusted so as to fallwithin desired proper limits by keeping the temperature in attachingglasses to each other by heat and pressure within a range of 60 to 100°C. and appropriately setting various conditions such as a pressure forattaching by pressure, a time for attaching by pressure and a vacuum indeaerating by aspiration within a range of the extent described above.

Since the laminated glass of the present invention has an HIC value(EEVC) of 1,000 or lower or an HIC value (ECE) of 300 or lower, itbecomes one which have the high performance for mitigating the impactgiven externally and, particularly in the case of using it as glass forvehicles, have the high performance for mitigating the impact when headcomes into collision with the glass due to the occurrence of a personalaccident.

When the laminated glass of the present invention is used as glass forvehicles and fixed to a window's frame, there is tendency that the HICvalue is higher particularly at locations close to the window's frameand the lower end of the window. And, in the occurrence of a personalaccident, a probability that a location with which the head of apedestrian comes into collision is a lower end of the glass for vehicles(especially a windshield) is high. Therefore, the laminated glass may beadjusted in such a way that the HIC value particularly in a locationclose to the window's frame and the lower end of the window is low. Thatis, by use of the interlayer film for laminated glasses having wedgedform that thickness increases gradually from one end toward the otherend or the interlayer film for laminated glasses having a configurationin which peripheral portion is more thick than a central portion, it ispossible to make the HIC value low particularly in a location close tothe window's frame and the lower end of the window.

In such a laminated glass, an interlayer film for laminated glasses,comprising only a single layer and having wedged form, may be used, butit is preferred to use an interlayer film for laminated glasses, forexample, which has a multilayer structure of three-layers or more and inwhich each layer has wedged form and the layer having wedged form isalternately overlaid with the layer of wedged having a small storageelasticity modulus G′ taken as an intermediate layer so that an overallthickness becomes uniform. When a windshield comprising the laminatedglass using such an interlayer film for laminated glasses having amultilayer structure is arranged in such a way that a base of wedgedform of the intermediate layer having a small storage elasticity modulusG′ is located at a lower end, an HIC value of a lower end of thewindshield in which there is a high risk of collision can be reduced,and in addition an upper end of the windshield in which there is a lowrisk of collision can secure strength.

The interlayer film for laminated glasses thus constructed can beproduced by using a die which can perform profile extrusion andconducting multi-layer extrusion in such a way that every layer becomeswedged.

In the laminated glass of the present invention, it is preferred thatelectromagnetic wave shielding performance in frequencies of 0.1 to 26.5GHz is 10 dB or less, haze is 1% or lower, visible transmittance is 70%or higher, and solar radiation transmittance in a wavelength region of300 nm to 2,100 nm is 85% or lower of visible transmittance. And, solarradiation transmittance in a wavelength region of 300 nm to 2,100 nm ispreferably 80% or lower of visible transmittance. The laminated glass ofthe present invention satisfying such conditions satisfies theperformance of protecting pedestrians by the low HIC value andsimultaneously allows an amount of heat rays from solar radiationreaching the vehicle's interior to decrease, and therefore a temperaturerise within interior of the automobile can be suppressed and acomfortable interior space can be realized. And, since the laminatedglass of the present invention has the electromagnetic wave transparencyin a frequency band of 0.1 to 26.5 GHz, it can transmit electromagneticwave in a frequency band required for information communication such as3.5 MHz band and 7 MHz band of amateur radio, a frequency band of 10 MHzor lower of emergency communication, 2.5 GHz of VICS (the VehicleInformation Communication System), 5.8 GHz of ETC (Electronic TollCollections) and 12 GHz of satellite broadcasting without problems.

In order to impart such a function to the laminated glass of the presentinvention, the polyvinyl acetal resin, constituting the interlayer filmfor laminated glasses, preferably contains metal oxide particles havinga function of screening out heat rays. In addition, when the interlayerfilm for laminated glasses has a multilayer structure, polyvinyl acetalresin of at least one layer may contains metal oxide particles having afunction of screening out heat rays.

The above-mentioned particles of metal oxide is not particularly limitedbut for example, tin-doped indium oxide and/or antimony-doped tin oxideis suitable. Preferably, the above-mentioned tin-doped indium oxideand/or antimony-doped tin oxide has an average diameter of secondaryparticles formed by flocculation of 80 nm or smaller and is dispersed inpolyvinyl acetal resin in such a way that a secondary particle formed byflocculation of 100 nm or larger in diameter has a density of 1particle/μm² or less in polyvinyl acetal resin. When a state ofdispersion of the particles of metal oxide was out of theabove-mentioned range, the transparency of visible light of thelaminated glass to be obtained may be deteriorated or haze may becomelarger.

As for the content of the above-mentioned particles of metal oxide, apreferable lower limit is 0.05 parts by weight and a preferable upperlimit is 5.0 parts by weight with respect to 100 parts by weight ofpolyvinyl acetal resin. When the content is less than 0.05 parts byweight, an adequate effect of screening out heat rays may not beattained, and when it is more than 5.0 parts by weight, the transparencyof visible light of the laminated glass to be obtained may bedeteriorated or haze may become larger.

Further, when the interlayer film for laminated glasses has a multilayerstructure, a preferable lower limit is 0.05 parts by weight and apreferable upper limit is 5.0 parts by weight with respect to 100 partsby weight of polyvinyl acetal resin in all layers.

EFFECT OF THE INVENTION

In accordance with the present invention, it is possible to provide to alaminated glass and an interlayer film for laminated glasses, which havethe high performance for mitigating the impact given externally and,particularly in the case of using it as glass for vehicles, have thehigh performance for mitigating the impact when head comes intocollision with the glass due to the occurrence of a personal accident.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in details withreference to examples, however the present invention is not limited tothese examples.

Example 1 (1) Preparation of Interlayer Film for Laminated Glass

100 parts by weight of polyvinyl butyral resin (an acetalization degree68.0 mole %, a proportion of a vinyl acetate component 0.6 mole %), inwhich a half band width of a peak, obtained in measuring infraredabsorption spectra, corresponding to a hydroxyl group is 245 cm⁻¹, and38 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film having athickness of 800 μm and this film was employed as an interlayer film forlaminated glasses.

Next, the resulting interlayer film for laminated glasses was sandwichedbetween two clear float glasses of 2 mm in thickness and this was put ina rubber bag and deaerated at a vacuum of 2,660 Pa for 20 minutes, andthen this was moved into an oven in a state of being deaerated andsubjected to vacuum press while being further retained at 90° C. for 30minutes. A laminated glass formed preliminarily by thus attaching thefloat glass to each other by applying pressure was subjected toattaching by pressure under the conditions of 135° C. and a pressure of118 N/cm² for 20 minutes in an autoclave to obtain a laminated glass.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated according to the following methods.

The results are shown in Table 1.

(Measurement of HIC Value (EEVC))

An HIC value (EEVC) of the laminated glass was measured using anapparatus for measuring HIC having a structure shown in FIG. 1. When theHIC value is 1,000 or lower, the laminated glass is rated as acceptance(o), and when the HIC value is higher than 1,000, it is rated asinacceptance (x).

(Measurement of HIC Value (ECE))

An HIC value (ECE) of the laminated glass was measured by dropping animpactor head from a height of 4 m above the surface of the laminatedglass and allowing the impactor to collide against the laminated glassusing an apparatus for measuring HIC having a structure shown in FIG. 2.

Further, when a break is generated in the interlayer film for laminatedglasses during the measurement, the length of the break was measured.

(Measurement of Maximum Stress σ, Fracture Point Deformation ε andBreaking Energy U of Interlayer Film for Laminated Glasses)

The interlayer film for laminated glass was processed into a dumbbellNo. 1 (according to JIS K 6771) specimen and stretched at a tensilespeed of 500%/min using a tension tester and breaking tensile strength(kg/cm²) was measured at a measuring temperature of 20° C. A stress σ(MPa)—deformation ε (%) curve was determined from the obtained data.Here, 500%/min means a speed of moving the distance 5 times longer thanthat between chucks of a specimen per 1 minute.

Next, maximum stress σ and fracture point deformation ε are determinedfrom the obtained stress-deformation curve and breaking energy U wasderived from the above-mentioned equation (2).

(Measurement of Storage Elasticity Modulus G′ and Tan δ of Resin Filmand Interlayer Film for Laminated Glasses)

Shear viscoelasticity in the range of 50 to 100 Hz was measured at 20°C. using a dynamic viscoelasticity measuring apparatus (apparatus;DVA-200, manufacturer; IT Keisoku Seigyo Co., Ltd.), and a maximum valueof storage elasticity modulus obtained in measuring is taken as G′ (max)and a minimum value is taken as G′ (min) and a maximum value of tan δobtained in measuring is taken as tan δ (max).

Example 2

100 parts by weight of polyvinyl butyral resin (an acetalization degree68.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and38 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film having athickness of 1,500 μm and this film was employed as an interlayer filmfor laminated glasses. And, using the obtained interlayer film forlaminated glasses, a laminated glass was obtained by following the sameprocedure as in Example 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 3

100 parts by weight of polyvinyl butyral resin (an acetalization degree68.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and45 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film having athickness of 760 μm and this film was employed as an interlayer film forlaminated glasses. And, using the obtained interlayer film for laminatedglasses, a laminated glass was obtained by following the same procedureas in Example 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 4

100 parts by weight of polyvinyl butyral resin (an acetalization degree68.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and38 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (1) having athickness of 340 μm.

Next, 100 parts by weight of polyvinyl butyral resin (an acetalizationdegree 65.0 mole %, a proportion of a vinyl acetate component 14 mole %)and 62 parts by weight of triethylene glycol-di-2-ethylhexanoate (3GO)as a plasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (2) having athickness of 120 μm.

A storage elasticity modulus G′ and tan δ of the obtained resin filmswere measured by the method described above.

The results are shown in Table 2.

The resulting resin film (2) was sandwiched between two resin films (1)and these films were attached to each other by heat and pressure byconducting heating press to obtain an interlayer film for laminatedglasses having a three-layers structure. In FIG. 3, there is shown aschematic view showing a constitution of the obtained interlayer filmfor laminated glasses.

And, using the obtained interlayer film for laminated glasses, alaminated glass was obtained by following the same procedure as inExample 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 5

100 parts by weight of polyvinyl butyral resin (an acetalization degree68.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and38 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (3) having athickness of 250 μm.

Next, 100 parts by weight of polyvinyl butyral resin (an acetalizationdegree 65.0 mole %, a proportion of a vinyl acetate component 14 mole %)and 60 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO)as a plasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (4) having athickness of 250 μm.

A storage elasticity modulus G′ and tan δ of the obtained resin filmswere measured by the method described above.

The results are shown in Table 2.

The resulting resin film (4) was sandwiched between two resin films (3)and these films were attached to each other by heat and pressure byconducting heating press to obtain an interlayer film for laminatedglasses having a three-layers structure. In FIG. 4, there is shown aschematic view showing a constitution of the obtained interlayer filmfor laminated glasses.

And, using the obtained interlayer film for laminated glasses, alaminated glass was obtained by following the same procedure as inExample 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 6

100 parts by weight of polyvinyl butyral resin (an acetalization degree68.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and38 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (5) having athickness of 300 μm.

Next, 100 parts by weight of polyvinyl butyral resin (an acetalizationdegree 65.0 mole %, a proportion of a vinyl acetate component 14 mole %)and 60 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO)as a plasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (6) having athickness of 300 μm.

A storage elasticity modulus G′ and tan δ of the obtained resin filmswere measured by the method described above.

The results are shown in Table 2.

The resulting resin film (6) was sandwiched between two resin films (5)and these films were attached to each other by heat and pressure byconducting heating press to obtain an interlayer film for laminatedglasses having a three-layers structure. In FIG. 5, there is shown aschematic view showing a constitution of the obtained interlayer filmfor laminated glasses.

And, using the obtained interlayer film for laminated glasses, alaminated glass was obtained by following the same procedure as inExample 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 7

100 parts by weight of polyvinyl butyral resin (an acetalization degree68.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and38 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (7) having athickness of 500 μm and a resin film (8) having a thickness of 200 μm.

A storage elasticity modulus G′ and tan δ of the obtained resin filmswere measured by the method described above.

The results are shown in Table 2.

The resin film (4) obtained in Example 5 was sandwiched between theobtained resin film (7) and the obtained resin film (8) and these filmswere attached to each other by heat and pressure by conducting heatingpress to obtain an interlayer film for laminated glasses having athree-layers structure. In FIG. 6, there is shown a schematic viewshowing a constitution of the obtained interlayer film for laminatedglasses.

And, using the obtained interlayer film for laminated glasses, alaminated glass was obtained by following the same procedure as inExample 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1. In addition, an HICvalue (EEVC) and an HIC value (ECE) were measured by colliding animpactor head to the surface of glass bonded to the side of the resinfilm (8).

Example 8

100 parts by weight of polyvinyl butyral resin (an acetalization degree65.0 mole %, a proportion of a vinyl acetate component 14 mole %) and 50parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (9) having athickness of 450 μm.

A storage elasticity modulus G′ and tan δ of the obtained resin filmwere measured by the method described above.

The results are shown in Table 2.

The resin film (5) obtained in Example 6 was superimposed over theobtained resin film (9), and the superimposed resin films were attachedto each other by heat and pressure by conducting heating press to obtainan interlayer film for laminated glasses having a two-layers structure.In FIG. 7, there is shown a schematic view showing a constitution of theobtained interlayer film for laminated glasses.

And, using the obtained interlayer film for laminated glasses, alaminated glass was obtained by following the same procedure as inExample 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1. In addition, an HICvalue (EEVC) and an HIC value (ECE) were measured by colliding animpactor head for measuring HIC to the surface of glass bonded to theside of the resin film (5).

Example 9

The resin film (7) obtained in Example 7 was sandwiched between tworesin films (2) obtained in Example 3, and these films were attached toeach other by heat and pressure by conducting heating press to obtain aninterlayer film for laminated glasses having a three-layers structure.In FIG. 8, there is shown a schematic view showing a constitution of theobtained interlayer film for laminated glasses.

And, using the obtained interlayer film for laminated glasses, alaminated glass was obtained by following the same procedure as inExample 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 10

The resin film (7) obtained in Example 7 was sandwiched between theresin film (2) obtained in Example 3 and the resin film (5) obtained inExample 6, and these films were attached to each other by heat andpressure by conducting heating press to obtain an interlayer film forlaminated glasses having a three-layers structure. In FIG. 9, there isshown a schematic view showing a constitution of the obtained interlayerfilm for laminated glasses.

And, using the obtained interlayer film for laminated glasses, alaminated glass was obtained by following the same procedure as inExample 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1. In addition, an HICvalue (EEVC) and an HIC value (ECE) were measured by colliding animpactor head for measuring HIC to the surface of glass bonded to theside of the resin film (5).

Example 11

100 parts by weight of polyvinyl butyral resin (an acetalization degree65.0 mole %, a proportion of a vinyl acetate component 14 mole %), inwhich a half band width of a peak, obtained in measuring infraredabsorption spectra, corresponding to a hydroxyl group is 190 cm⁻¹, and45 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film having athickness of 760 μm and this film was employed as an interlayer film forlaminated glasses. And, using the obtained interlayer film for laminatedglasses, a laminated glass was obtained by following the same procedureas in Example 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 12

An aqueous solution of polyvinyl alcohol, which was formed by dissolvingpolyvinyl alcohol having an average polymerization degree of 1,500 and asaponification degree of 99.5 mole % in pure water so as to be 10% byweight in concentration, was prepared. To 100 parts by weight of thisaqueous solution of polyvinyl alcohol were added 0.8 parts by weight of10% hydrochloric acid as an acid catalyst and 5.73 parts by weight ofbutylaldehyde. Then, this mixture was reacted at 85 to 95° C. for onehour while being stirred. Then, 3.5 parts by weight of 10% hydrochloricacid as an acid catalyst was added to the mixture and the mixture wasreacted at 85° C. for 2 hours while being stirred to obtain particles ofa crosslinked polyvinyl butyral resin. An average particle diameter ofthe obtained crosslinked polyvinyl butyral resin particle was 1.0 μm.

100 parts by weight of polyvinyl butyral resin (an acetalization degree65.0 mole %, a proportion of a vinyl acetate component 0.6 mole %), 30parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer and 5 parts by weight of the obtained crosslinked polyvinylbutyral resin particles were mixed, and the mixture was adequatelymelted and kneaded with a mixing roller and then was formed at 150° C.for 30 minutes with a press forming machine to obtain a resin filmhaving a thickness of 760 μm and this film was employed as an interlayerfilm for laminated glasses. And, using the obtained interlayer film forlaminated glasses, a laminated glass was obtained by following the sameprocedure as in Example 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

Example 13

100 parts by weight of crosslinked polyvinyl butyral resin prepared inExample 12 and 40 parts by weight of triethylene glycoldi-2-ethylbutyrate as a plasticizer were mixed, and the mixture wasadequately melted and kneaded with a kneader and then was formed at 150°C. and a pressure of 980 N/cm² for 20 minutes with a press formingmachine to obtain a resin film having a thickness of 860 μm and thisfilm was employed as an interlayer for laminated glass. And, using theobtained interlayer film for laminated glasses, a laminated glass wasobtained by following the same procedure as in Example 1.

The obtained interlayer film for laminated glasses and laminated glasswere evaluated in the same manner as in Example 1.

TABLE 1 Example Example Example Example Example Example Example 1 2 3 45 6 7 Storage elasticity 4.3 × 10⁷ 4.2 × 10⁷ 2.7 × 10⁷ 2.6 × 10⁶ 1.5 ×10⁶ 1.0 × 10⁶ 1.7 × 10⁶ modulus G′ (max) (Pa) tan δ (max) 0.54 0.55 0.540.70 0.76 0.83 0.74 Maximum 26.4 38.2 17.5 25.3 14.3 15.8 15.8 stress σ(MPa) Fracture point 440 320 450 450 340 370 320 deformation ε (%)Breaking energy U 1.7 1.9 1.2 2.0 0.75 1.1 1.3 (J/mm²) Correspondingdrawing — — — 3 4 5 6 of the case of multilayer structure Ratio ofthickness of — — — 15.0 33.3 33.3 26.3 layer having G′ of 2 × 10⁶ Pa orsmaller (%) HIC value (EEVC) ◯ ◯ ◯ ◯ ◯ ◯ ◯ HIC value (ECE) 281 375 215240 174 169 167 Length of break in 0 0 0 0 60 95 50 interlayer (mm)Example Example Example Example Example Example 8 9 10 11 12 13 Storageelasticity 2.0 × 10⁶ 2.1 × 10⁶ 1.9 × 10⁶ 3.8 × 10⁷ 4.3 × 10⁷ 4.0 × 10⁷modulus G′ (max) (Pa) tan δ (max) 0.81 0.77 0.80 0.61 0.61 0.56 Maximum17.0 15.1 12.4 15.9 19.5 16.2 stress σ (MPa) Fracture point 390 350 380420 420 380 deformation ε (%) Breaking energy U 1.2 0.89 0.79 1.1 1.61.3 (J/mm²) Corresponding drawing 7 8 9 — — — of the case of multilayerstructure Ratio of thickness of — 32.4 45.7 — — — layer having G′ of 2 ×10⁶ Pa or smaller (%) HIC value (EEVC) ◯ ◯ ◯ ◯ ◯ ◯ HIC value (ECE) 170181 171 234 242 222 Length of break in 55 70 80 0 0 0 interlayer (mm)

TABLE 2 Resin film Resin film Resin film Resin film Resin film Resinfilm Resin film Resin film Resin film (1) (2) (3) (4) (5) (6) (7) (8)(9) Storage elasticity — 6.8 × 10⁵ — 6.7 × 10⁵ — 6.7 × 10⁵ — — 1.5 × 10⁶modulus G′ (max) (Pa) Storage elasticity 4.5 × 10⁷ — 4.3 × 10⁷ — 4.3 ×10⁷ — 4.3 × 10⁷ 4.3 × 10⁷ — modulus G′ (min) (Pa) tan δ (max) 0.56 0.990.55 1.00 0.55 0.99 0.54 0.55 0.90 Thickness (μm) 340 120 250 250 300300 500 200 450

Example 14

The interlayer film for laminated glasses obtained by following the sameprocedure as in Example 1 was sandwiched between two clear float glassesof 1.8 mm and 4 mm in thickness, respectively, and this was put in arubber bag and deaerated at a vacuum of 2,660 Pa for 20 minutes, andthen this was moved into an oven in a state of being deaerated andsubjected to vacuum press while being further retained at 90° C. for 30minutes. A laminated glass formed preliminarily by thus attaching thefloat glass to each other by applying pressure was subjected toattaching by pressure under the conditions of 135° C. and a pressure of118 N/cm² for 20 minutes in an autoclave to obtain a laminated glass.

An HIC value (EEVC) and an HIC value (ECE) of the obtained laminatedglass were measured by colliding an impactor head for measuring HIC tothe glass on the side of the float glass of 4 mm in thickness by themethod described above.

The results are shown in Table 3.

Example 15

An HIC value (EEVC) and an HIC value (ECE) of the laminated glassobtained by following the same procedure as in Example 14 were measuredby colliding an impactor head for measuring HIC to the glass on the sideof the float glass of 1.8 mm in thickness by the method described above.

The results are shown in Table 3.

Example 16

The interlayer film for laminated glasses obtained by following the sameprocedure as in Example 1 was sandwiched between a float glasses of 2.5mm in thickness and polymethyl methacrylate of 1.0 mm in thickness,which is provided with a scratch protection layer comprising transparentelastomer on the surface, and this was put in a rubber bag and deaeratedat a vacuum of 2,660 Pa for 20 minutes, and then this was moved into anoven in a state of being deaerated and subjected to vacuum press whilebeing further retained at 90° C. for 30 minutes. A laminated glassformed preliminarily by thus attaching the float glass and polymethylmethacrylate to each other by applying pressure was subjected toattaching by pressure under the conditions of 135° C. and a pressure of118 N/cm² for 20 minutes in an autoclave to obtain a laminated glass.

An HIC value (EEVC) and an HIC value (ECE) of the obtained laminatedglass were measured by colliding an impactor head for measuring HIC tothe glass on the side of the float glass by the method described above.

The results are shown in Table 3.

Example 17

100 parts by weight of polyvinyl butyral resin (an acetalization degree65.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and30 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine. In forming by a press formingmachine, the resin was processed in such a way that a thickness of anend of one side is 660 μm and a thickness of an opposite end of otherside is 860 μm to obtain a resin film of wedged and this resin film wasemployed as an interlayer film for laminated glasses.

A laminated glass was prepared by following the same procedure as inExample 1 except for using the obtained interlayer film for laminatedglasses.

An HIC value (EEVC) and an HIC value (ECE) of the obtained laminatedglass were measured by the method described above.

The results are shown in Table 3.

Example 18

A resin film of 100 μm in thickness comprising polyethyleneterephthalate was sandwiched between two resin films (1) obtained inExample 4, and these films were attached to each other by heat andpressure by conducting heating press to obtain an interlayer film forlaminated glasses having a three-layers structure. In FIG. 10, there isshown a schematic view showing a constitution of the obtained interlayerfilm for laminated glasses.

A laminated glass was prepared by following the same procedure as inExample 1 except for using the obtained interlayer film for laminatedglasses.

An HIC value (EEVC) and an HIC value (ECE) of the obtained laminatedglass were measured by the method described above.

The results are shown in Table 3.

Example 19

100 parts by weight of polyvinyl butyral resin (an acetalization degree65.0 mole %, a proportion of a vinyl acetate component 0.6 mole %) and30 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) as aplasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine. In forming by a press formingmachine, there was obtained a resin film (10) in wedged form having across section of a right-angled triangle of 430 μm in base and 500 mm inheight.

And, 100 parts by weight of polyvinyl butyral resin (an acetalizationdegree 65.0 mole %, a proportion of a vinyl acetate component 14 mole %)and 50 parts by weight of triethylene glycol di-2-ethylhexanoate (3GO)as a plasticizer were mixed, and the mixture was adequately melted andkneaded with a mixing roller and then was formed at 150° C. for 30minutes with a press forming machine to obtain a resin film (11) inwedged form having a cross section of a isosceles triangle of 860 μm inbase and 500 mm in height.

Two resin films (10) in wedged form having a cross section of aright-angled triangle were laminated on the resin film (11) in wedgedform having a cross section of a isosceles triangle, and this laminatewas employed as an interlayer for laminated glass having a uniformthickness.

A laminated glass was prepared by following the same procedure as inExample 1 except for using the obtained interlayer film for laminatedglasses. In FIG. 11, there is shown a schematic view showing aconstitution of the obtained interlayer film for laminated glasses.

An HIC value (EEVC) and an HIC value (ECE) of the obtained laminatedglass were measured by the method described above.

The results are shown in Table 3.

Example 20

5-mm-long straight slits were cut with 20-mm pitches in the surface of aresin film of 100 μm in thickness comprising polyethylene terephthalate.Further, similar straight slits parallel to one another were cut with100-mm pitches throughout the resin film comprising polyethyleneterephthalate.

The obtained resin film, in the surface of which slits was cut, having athickness of 100 μm and comprising polyethylene terephthalate wassandwiched between two resin films (1) obtained in Example 4, and thesefilms were attached to each other by heat and pressure by conductingheating press to obtain a interlayer film for laminated glasses having athree-layers structure. In FIG. 12, there is shown a schematic viewshowing a constitution of the obtained interlayer film for laminatedglasses.

A laminated glass was prepared by following the same procedure as inExample 1 except for using the obtained interlayer film for laminatedglasses.

An HIC value (EEVC) and an HIC value (ECE) of the obtained laminatedglass were measured by the method described above.

The results are shown in Table 3.

TABLE 3 Example14 Example15 Example16 Example17 Example18 Example19Example20 HIC value (EEVC) ◯ ◯ ◯ ◯ ◯ ◯ ◯ HIC value (ECE) 222 225 262 278350 200 185 Corresponding drawing — — — — 10 11 12 of the case ofmultilayer structure Length of break in the 0 0 0 0 0 0 105 interlayer(mm)

Example 21 Preparation of ITO-Dispersed Plasticizer

Into 100 parts by weight of triethylene glycol di-2-ethylhexanoate(3GO), 2.5 parts by weight of tin-doped indium oxide (ITO) powder wascharged and the ITO particles was dispersed in 3GO with a horizontalmicrobead mill using polyphosphate salt as a dispersant. Then, to theresulting dispersion, 0.25 parts by weight of acetyl acetone was addedwhile stirring to obtain an ITO-dispersed plasticizer.

An interlayer film for laminated glasses, having a thickness of 800 μm,was prepared by following the same procedure as in Example 1 except forusing 38 parts by weight of an ITO-dispersed plasticizer obtained inplace of 38 parts by weight of triethylene glycol di-2-ethylhexanoate(3GO), and using this, a laminated glass was prepared.

Example 22

A resin film (12) having a thickness of 340 μm was prepared by followingthe same procedure as in Example 4 except for using 38 parts by weightof an ITO-dispersed plasticizer obtained in Example 20 in place of 38parts by weight of triethylene glycol di-2-ethylhexanoate (3GO) inpreparation on the resin film (1).

And, a resin film (13) having a thickness of 120 μm was prepared byfollowing the same procedure as in Example 4 except for using 62 partsby weight of the ITO-dispersed plasticizer obtained in Example 20 inplace of 62 parts by weight of triethylene glycol di-2-ethylhexanoate(3GO) in preparation on the resin film (2).

A storage elasticity modulus G′ and tan δ of the obtained resin films(12) and (13) were measured by the method described above and further astate of dispersion of ITO particles was evaluated by the followingmethod. The results are shown in Table 4.

(Evaluation of State of Dispersion of ITO Particles)

An ultra-thin slice of a section of an interlayer for laminated glasswas prepared and photography was conducted using a transmission electronmicroscope (TEM; H-7100 FA manufactured by Hitachi, Ltd.). In addition,an area of 3 μm×4 μm was photographed at a magnification of 20,000 timesand this photograph was enlarged to 3 times in a printing stage.

Longer diameters of particle diameters of all ITO particles in photoscope of 3 μm×4 μm were measured and an average particle diameter wasderived by a cumulative average. Further, number of particles of 100 nmor larger in particle diameter existing in a photo scope was determinedand by dividing this number of particles by a photo area of 12 μm²,number of particles per 1 μm² was determined.

The resin film (13) was sandwiched between two resin films (12) andthese films were attached to each other by heat and pressure byconducting heating press to obtain an interlayer film for laminatedglasses having a three-layers structure. In FIG. 13, there is shown aschematic view showing a constitution of the obtained interlayer filmfor laminated glasses.

Using the obtained interlayer film for laminated glasses, a laminatedglass was obtained by following the same procedure as in Example 1.

Example 23

The resin film (2) obtained in Example 4 was sandwiched between tworesin films (12) obtained in Example 21 and these films were attached toeach other by heat and pressure by conducting heating press to obtain aninterlayer film for laminated glasses having a three-layers structure.In FIG. 14, there is shown a schematic view showing a constitution ofthe obtained interlayer film for laminated glasses.

Using the obtained interlayer film for laminated glasses, a laminatedglass was obtained by following the same procedure as in Example 1.

Example 24 Preparation of ATO-Dispersed Plasticizer

Into 100 parts by weight of triethylene glycol di-2-ethylhexanoate(3GO), 3.0 parts by weight of antimony-doped tin oxide (ATO) powder wascharged and the ATO particles was dispersed in 3GO with a horizontalmicrobead mill using polyphosphate salt as a dispersant. Then, to theresulting dispersion, 0.25 parts by weight of acetyl acetone was addedwhile stirring to obtain an ATO-dispersed plasticizer.

And, a resin film (14) having a thickness of 120 μm was prepared byfollowing the same procedure as in Example 4 except for using 62 partsby weight of the ATO-dispersed plasticizer obtained in place of 62 partsby weight of triethylene glycol di-2-ethylhexanoate (3GO) in preparationon the resin film (2).

A storage elasticity modulus G′ and tan δ of the obtained resin film(14) were measured by the method described above and a state ofdispersion of ATO particles was evaluated by following the same methodas in ITO particles. The results are shown in Table 4.

The obtained resin film (14) was sandwiched between two resin films (1)obtained in Example 4 and these films were attached to each other byheat and pressure by conducting heating press to obtain an interlayerfilm for laminated glasses having a three-layers structure. In FIG. 15,there is shown a schematic view showing a constitution of the obtainedinterlayer film for laminated glasses.

Using the obtained interlayer film for laminated glasses, a laminatedglass was obtained by following the same procedure as in Example 1.

The interlayer film for laminated glasses and the laminated glassobtained in Examples 21 to 24 were evaluated in the same manner as inExample 1.

Further, electromagnetic wave transparency, visible transmittance, solarradiation transmittance and haze of the obtained laminated glass wereevaluated by the following method.

The results are shown in Table 5.

(Evaluation of Electromagnetic Wave Shielding Property in Frequencies of0.1 to 26.5 GHz)

Through measurements by a KEC method (measurement of electromagneticwave shielding effects in the close field), reflection loss values (dB)of glass in a range of 0.1 to 2 GHz were compared with those of a usualsingle sheet of float glass of 2.5 nm in thickness and minimum andmaximum values of the differences between both reflection loss values inthe above-mentioned frequencies were recorded. And, reflection lossvalues (dB) in a range of 2 to 26.5 GHz were measured by standing asample with a size of 600 mm square between a pair of the antennas forsending and receiving and radio waves from a radio signal generator werereceived with a spectrum analyzer and an electromagnetic wave shieldingproperty of the sample was evaluated (method of measuringelectromagnetic waves in the far field).

(Measurement of Haze)

Haze was measured according to JIS K 6714.

(Measurement of Visible Transmittance and Solar Radiation Transmittancein Wavelength Region of 300 nm to 2,100 nm)

The transmittance of light of 300 to 2,100 nm in wavelength was measuredusing a direct recording type Spectrophotometer (UV-3100 manufactured byShimadzu Corporation), and visible transmittance Tv of 380 to 780 nm inwavelength and solar radiation transmittance Ts of 300 to 2,100 nm inwavelength were determined according to JIS Z 8722 and JIS R 3106(1998).

TABLE 4 Resin Resin Resin film film film (12) (13) (14) Storageelasticity — 6.9 × 10⁵ 7.0 × 10⁵ modulus G′ (max) (Pa) Storageelasticity 4.7 × 10⁷ — — modulus G′ (min) (Pa) tan δ (max) 0.54 0.950.97 Thickness(μm) 340 120 120 Average particle 58 58 65 diameter of ITOor ATO (nm) Number of particles 0 0 0 of 100 nm or larger per 1μm²(particle)

TABLE 5 Example Example Example Example 21 22 23 24 Storage elasticitymodulus 4.4 × 10⁷ 3.0 × 10⁶ 2.6 × 10⁶ 2.9 × 10⁶ G′ (max) (Pa) tan δ(max) 0.55 0.66 0.71 0.68 Maximum stress σ (MPa) 27.0 27.0 25.8 26.3Fracture point 400 390 400 420 deformation ε (%) Breaking energy U 1.92.2 2.3 2.2 (J/mm²) Corresponding drawing of — 13 14 15 the case ofmultilayer structure Ratio of thickness of layer — 15.0 15.0 15.0 havingG′ of 2 × 10⁶ Pa or smaller (%) HIC value (EEVC) ◯ ◯ ◯ ◯ HIC value (ECE)290 255 244 239 Electromagnetic wave 0~1 0~1 0~1 0~1 shielding property

dB haze (%) 0.5 0.6 0.5 0.6 Visible transmittance Tv (%) 83 79 83 80Solar radiation 56 51 57 59 transmittance Ts (%) Length of break in the0 0 0 0 interlayer (mm)

INDUSTRIAL APPLICABILITY

In accordance with the present invention, it is possible to provide to alaminated glass and an interlayer film for laminated glasses, which havethe high performance for mitigating the impact given externally and,particularly in the case of using it as glass for vehicles, have thehigh performance for mitigating the impact when head comes intocollision with the glass due to the occurrence of a personal accident.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing schematically a sample ofan HIC measuring apparatus to measure HIC values (EEVC) of a laminatedglass of the present invention.

FIG. 2 is a schematic view showing a sample of an HIC measuringapparatus to measure HIC values (ECE) of the laminated glass of thepresent invention.

FIG. 3 is a schematic view showing a constitution of the interlayer filmfor laminated glasses obtained in Example 4.

FIG. 4 is a schematic view showing a constitution of the interlayer filmfor laminated glasses obtained in Example 5.

FIG. 5 is a schematic view showing a constitution of the interlayer filmfor laminated glasses obtained in Example 6.

FIG. 6 is a schematic view showing a constitution of the interlayer filmfor laminated glasses obtained in Example 7.

FIG. 7 is a schematic view showing a constitution of the interlayer filmfor laminated glasses obtained in Example 8.

FIG. 8 is a schematic view showing a constitution of the interlayer filmfor laminated glasses obtained in Example 9.

FIG. 9 is a schematic view showing a constitution of the interlayer filmfor laminated glasses obtained in Example 10.

FIG. 10 is a schematic view showing a constitution of the interlayerfilm for laminated glasses obtained in Example 18.

FIG. 11 is a schematic view showing a constitution of the interlayerfilm for laminated glasses obtained in Example 19

FIG. 12 is a schematic view showing a constitution of the interlayerfilm for laminated glasses obtained in Example 20.

FIG. 13 is a schematic view showing a constitution of the interlayerfilm for laminated glasses obtained in Example 22.

FIG. 14 is a schematic view showing a constitution of the interlayerfilm for laminated glasses obtained in Example 23.

FIG. 15 is a schematic view showing a constitution of the interlayerfilm for laminated glasses obtained in Example 24.

DESCRIPTION OF THE NUMERALS

-   10 apparatus for measuring HIC value (EEVC)-   11 supporting portion-   12 flange portion-   13 securing portion-   14 impactor head-   20 apparatus for measuring HIC value (ECE)-   21 laminated glass stage-   22 impactor head-   23 guide system-   24 optical sensor

1. An interlayer film for laminated glasses, wherein a break of 10 mm orlonger in length is generated when a laminated glass is formed bysandwiching the interlayer film for laminated glasses between twoglasses and a Head Injury Criteria (HIC) value of the laminated glass ismeasured, which has a three-layers structure, a storage elasticitymodulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in anintermediate layer being at or below a half of a storage elasticitymodulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one orany of two layers composing the outermost layer, wherein a thickness ofone outermost layer being 1.2 or more times larger than that of theother outermost layer.
 2. The interlayer film for laminated glassesaccording to claim 1, wherein a storage elasticity modulus G′ at 20° C.and a frequency of 5.0×10¹ to 1.0×10² Hz in the intermediate layer is2×10⁶ Pa or lower and a storage elasticity modulus G′ at 20° C. and afrequency of 5.0×10¹ to 1.0×10² Hz in one or any of two layers composingthe outermost layer is 1×10⁷ Pa or higher.
 3. The interlayer film forlaminated glasses according to claim 1, wherein the intermediate layerhas tan δ of 0.7 or more at 20° C. and a frequency of 5.0×10¹ to 1.0×10²Hz.
 4. The interlayer film for laminated glasses according to claim 1,wherein a thickness of the intermediate layer is 10% or higher of atotal thickness of the interlayer film for laminated glasses.
 5. Aninterlayer film for laminated glasses, wherein a break of 10 mm orlonger in length is generated when a laminated glass is formed bysandwiching the interlayer film for laminated glasses between twoglasses and a Head Injury Criteria (HIC) value of the laminated glass ismeasured, which has a three-layers structure, a storage elasticitymodulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one orany of two layers composing the outermost layer being at or below a halfof a storage elasticity modulus G′ at 20° C. and a frequency of 5.0×10¹to 1.0×10² Hz in an intermediate layer, wherein a thickness of oneoutermost layer being 1.2 or more times larger than that of the otheroutermost layer.
 6. The interlayer film for laminated glasses accordingto claim 5, wherein a storage elasticity modulus G′ at 20° C. and afrequency of 5.0×10¹ to 1.0×10² Hz in one or any of two layers composingthe outermost layer is 2×10⁶ Pa or lower and a storage elasticitymodulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in theintermediate layer is 1×10⁷ Pa or higher.
 7. The interlayer film forlaminated glasses according to claim 5, wherein tan δ at 20° C. and afrequency of 5.0×10¹ to 1.0×10² Hz in one or any of two layers composingthe outermost layer is 0.7 or more.
 8. The interlayer film for laminatedglasses according to claim 5, wherein a total thickness of the outermostlayer is 10% or higher of a total thickness of the interlayer film forlaminated glasses.
 9. An interlayer film for laminated glasses, whereina break of 10 mm or longer in length is generated when a laminated glassis formed by sandwiching the interlayer film for laminated glassesbetween two glasses and a Head Injury Criteria (HIC) value of thelaminated glass is measured, which has a multilayer structure offour-layers or more, a storage elasticity modulus G′ at 20° C. and afrequency of 5.0×10¹ to 1.0×10² Hz in at least one layer of anintermediate layer being at or below a half of a storage elasticitymodulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hz in one orany of two layers composing the outermost layer, wherein a thickness ofone outermost layer being 1.2 or more times larger than that of theother outermost layer.
 10. The interlayer film for laminated glassesaccording to claim 9, wherein a storage elasticity modulus G′ at 20° C.and a frequency of 5.0×10¹ to 1.0×10² Hz in one or any of two layerscomposing the outermost layer is 2×10⁶ Pa or lower and a storageelasticity modulus G′ at 20° C. and a frequency of 5.0×10¹ to 1.0×10² Hzin the intermediate layer is 1×10⁷ Pa or higher.
 11. The interlayer filmfor laminated glasses according to claim 9, wherein tan δ at 20° C. anda frequency of 5.0×10¹ to 1.0×10² Hz in one or any of two layerscomposing the outermost layer is 0.7 or more.
 12. The interlayer filmfor laminated glasses according to claim 9, wherein a total thickness ofthe outermost layer is 10% or higher of a total thickness of theinterlayer film for laminated glasses.